This patent document relates to techniques, devices and systems for exchanging information and establishing communications between two or more communication devices via capacitive coupling.
A capacitive sensor is a sensing device based on one or more capacitors which are coupled to a sensor circuit that applies an electrical signal to the one or more capacitors and measures the variation of signal due to a change that occurs at the one or more capacitors. This change can reflect one or more variations that affect the operation of the one or more capacitors, e.g., a change in relative spacing between two electrodes of a capacitor, a change in the relative position or overlap between two electrodes of a capacitor, a change in the dielectric material that affects the capacitance of a capacitor or a change in the electric field that affects the capacitance of a capacitor. Capacitor sensors can be configured to measure various parameters, such as motion, material composition, touch, object proximity, pressure, acceleration, and so on.
Some computers and communication devices use touch screens based on a 2-dimensional array of capacitor sensors to allow users to interact with the computers or devices by touching the touch screens. Various mobile phones and portable devices such as tablets use capacitor sensor touch screens to provide user friendly and intuitive user I/O interfaces for operating the mobile phones and portable devices.